鉴定7-脱氧-脱硫-基-圆柱体素,圆柱体素生物合成中缺失的部分
Annick Méjean1, Olivier Lequin2, Olivier Ploux1,3
1LIED, UMR 8236 CNRS, Université Paris Cité, 75205 Paris Cedex 13, France.
Journal of the American Chemical Society
|August 2, 2022
概括
研究人员在蓝藻细菌中发现了一种新型的圆柱培素前体,即7-deoxy-desulfo-argino-cylindrospermopsin. 他们阐明了它的生物合成,揭示了氨酸.
科学领域:
- 生物化学和分子生物学
- 环境微生物学 环境微生物学
- 自然产品化学 自然产品化学
背景情况:
- 圆柱是一种由淡水蓝藻细菌产生的显著毒素.
- 它的生物合成途径涉及多个多基酸合成酶和定制酶,从阿尔金因和甘氨酸开始.
- 乌拉环在圆柱种中的确切起源一直是一个长期存在的问题.
研究的目的:
- 为了识别和表征新型中间体在圆筒的生物合成.
- 阐明特定酶CyrG和CyrH在该途径中的作用.
- 为了确定 uracil 环的起源和圆筒产中的最后一个凝结步骤.
主要方法:
- 质谱测量用于代谢物识别.
- 1D和2DNMR光谱法用于结构阐明7-脱氧-脱硫-基-圆柱.
- 使用标记的阿尔金宁的同位素合并实验.
- 在大肠杆菌中的酶过度生产和净化.
- 酶分析和CyrG的动力分析.
- 生物信息分析包括基于结构的对齐和CyrF的二次结构预测.
主要成果:
- 鉴定和结构性确定7-脱氧-脱硫-氨-氨-氨-氨.
- 确认氨酸完全被纳入,其瓜尼迪诺部分形成了 uracil 环.
- CyrG被确定为一种依赖的酶,可以将7-deoxy-desulfo-argino-cylindrospermopsin转化为7-deoxy-desulfo-cylindrospermopsin和ornithine.
- 最终的多基基合成酶CyrF具有一种新的C端N-乙转移酶类域,该域被建议催化与氨酸的凝聚.
结论:
- 这项研究解决了长期存在的问题,即圆中 uracil 环的起源.
- 一种新的生物合成中间体和涉及CyrG和CyrF的酶步骤已经被描述.
- CyrF 独特域的拟议作用代表了前所未有的多基酸合成酶终结机制.
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